Cooling radiator for transformers



April 14, 1970 A. N. APPLEYARD ET 3,506,064

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April 14, 1970 APPLEYARD ET AL 3,506,064

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April 14, 1970 PP A ET AL 3,506,064

COOLING RADIATOR FOR TRANSFORMERS Filed May 17, 1968 3 Sheets-Sheet s 'NVEN DRS m NR1 7 -Yn@ FITRRNEY;

United States Patent 3,506,064 COOLING RADIATOR FOR TRANSFORMERS Alfred Noel Appleyard, Manchester, and Gregor Fyfe Clark, Cheshire, England, assignors to Associated Electrical Industries Limited, London, England, a British company Filed May 17, 1968, Ser. No. 729,986 Int. Cl. F28d 15/00 US. Cl. 165-106 4 Claims ABSTRACT OF THE DISCLOSURE A plate-type radiator, particularly suitable for cooling large oil immersed electrical transformers, having a plurality of radiator elements communicating with a header, and in which the latter is formed from tubular portions extending laterally from the individual elements and fitting one within the other, such an arrangement providing an economical construction with the absence of appreciable air traps.

This invention relates to radiators, for dissipating heat from fluids, of the kind comprising a plurality of hollow radiator elements communicating with at least one common duct forming a header. Such radiators, with headers at both ends of the elements, are employed for instance for the cooling of large oil-immersed electrical transformers, the oil being circulated through the radiator elements to dissipate heat from the oil. They may also be employed for the cooling of other liquid-immersed apparatus or for other purposes, for example space heating.

For transformer applications, very large numbers of these radiators are required because a single transformer may require up to four million square inches of cooling surfaces; the cooling equipment costs are therefore a major item of a transformer installation and economical radiator manufacture is thus very necessary.

An economical construction for the elements as such may be achieved in known manner by forming each element from two thin steel sheets joined at their edges to contain the oil or other liquid, the joining being usually effected by resistance, atomic hydrogen or gas welding. Such elements are thus plate-like and radiators comprising them are known as plate-type radiators. To improve the mechanical resistance of the element to deformation when subjected to external or internal pressures, the sheets are usually formed with corrugations and Welded together at intermediate positions. However, radiators of this type as are constructed hitherto have certain drawbacks, and an object of the present invention is to provide an alternative form of radiator suitable for use in cooling oil immersed electrical transformers which is constructed in a particularly advantageous manner.

According, therefore, to the invention a radiator for dissipating heat from fluid within it comprises a plurality of hollow radiator elements in communication with a header comprising tubular portions formed integrally with and extending laterally from the individual elements such that neighbouring elements have such portions extending towards one another with the end of the one portion fitting into the end of the other and joined thereto in fluid tight manner, preferably by resistance welding of their overlapping surfaces.

The invention will now be further explained by reference to FIGURES 1 to of the accompanying drawings in which FIGURES 1 and 1A illustrate part of a typical plate-type radiator element, FIGURES 2 to 4 illustrate known constructions of such radiators for cooling transformers and other apparatus, and FIGURE 5 illustrates the. alternative construction in accordance with the invention.

3,506,064 Patented Apr. 14, 1970 Referring first to FIGURE 1 and FIGURE 1A, these illustrate respectively a perspective view and a transverse cross-sectional view, on a larger scale, of part of a platetype radiator element as described above. In this construction the element 2 is divided by resistance-welded scams 4 into a number of longitudinal passages 6 for the liquid; the radiator is normally mounted so that these passages are vertical. The welded joint at the edges of the plate may be either an edge weld 8 formed by gas welding or a resistance weld 10 between flat surfaces adjacent to the edge, both of these alternatives being shown in the figures although only one would normally be used.

The chief constructional dilferences between one make of plate-type radiator and another occur in the headers at the respective ends of the elements. FIGUR'ES 2, 3 and 4 illustrate sectional views of three different wellknown constructions which may be briefly described as follows.

In the construction shown in FIGURE 2 each element 2 is joined to a header plate 12 by means of a ferrule 14. This involves hydrogen welding of the ferrules into the element ends at 16 and arc welding of the ferrules into the header plate at 18. Further welding is required at 20 between the header plate and a header cover 22. This construction is therefore expensive.

In the construction shown in FIGURE 3 the header is formed integrally with the elements 2" whose ends are formed as short laterally extending tubes 24 which abut with one another and are joined by hand gas-welds 26. This is also an expensive process compared with resistance welding.

The construction shown in FIGURE 4 is basically similar to that shown in FIGURE 3 but in this case the ends of the tubular header portions 24' are formed with inwardly extending flanges 28 which abut and can be joined by resistance welding as shown at 30. It is therefore more economical to produce but results in the formation of large air traps in the spaces 32 above the level of the edges of the welded flanges 28 in the upper header. This is a very undesirable feature in radiators for high voltage transformers.

FIGURE 5 illustrates, by way of example, a crosssectional side view of a portion, including part of a header and the adjacent parts of three radiator elements communicating therewith, of a radiator in accordance with the invention. The elements 2" are of the construction described with reference to FIGURES l and 1A and are formed at their header ends with transversely extending tubular portions 34 of such relative sizes that adjacent portions of neighbouring elements fit one within the other. Their overlapping surfaces 36 are joinedat 38 by resistance welding such as to make the joint fluid-tight. Thus, the header is composed of the transverse tubular portions of the elements.

As can be seen in FIG. 5 the illustrated construction has negligible air traps and, by virtue of the simple form of the tubular header portions and their suitability for resistance welding, it can be economically mass produced.

We claim:

1. A radiator for dissipating heat from fluid within it, said radiator comprising a plurality of hollow radiator elements, a header with which said radiator elements are in communication, said header including tubular portions formed integrally with and extending laterally from the individual radiator elements, each tubular portion having tubular terminals, each individual tubular terminal being of uniform diameter end to end, the tubular terminals of adjacent radiator elements being in mutually axial alignment and mutually forming a coupling pair, the tubular terminals constituting each coupling pair extending toward one another, one tubular terminal of each coupling pair being smaller in diameter than the diameter of the other tubular terminal and fitting telescopically into said other tubular terminal, and means joining said telescopically interfitted tubular terminal of each pair in a fluid tight manner.

2. A radiator as set forth in claim 1 wherein the resistance welded connections of the overlapping surface of the telescopically interfitting tubular terminals constitutes the means joining said transformers.

3. A fluid-filled electrical transformer having cooling radiators for dissipating heat from said fluid, each radiator comprising a plurality of hollow radiator elements, a header with which said radiator elements are in communication, said header including tubular portions formed integrally with and extending laterally from the individual radiator elements, each tubular portion having tubular terminals, each individual tubular terminal being of uniform diameter end to end, the tubular terminals of adjacent radiator elements being in mutually axial alignment and mutually forming a coupling pair, the tubular terminals constituting each coupling pair extending toward one another, one tubular terminal of each coupling pair .being smaller in diameter than the diameter of the other References Cited UNITED STATES PATENTS 4/1924 LoW 165106 5/1927 Dann 165106 ROBERT A. OLEARY, Primary Examiner C. SUKALO, Assistant Examiner US. Cl. X.R. 165--l75 

